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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f749d6d5b33e0c543aa3ab4faf04f27a37d0da736aa1c21631edf4f32bfa78a2' 
  AND token = '5DO7pHEQ7cJCDoXSg8mOWek5UbBw5k8nBHrsDlgJU7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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