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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e539cecf9de1653ee3ea94044bdd236e6189e43148df26a7b92407c1f8e35b' 
  AND token = 'dJc67gR9BkofjwyYNxVatbESsWPqKkeL8IyRzwMZQ14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}