SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dec2adaff3fbea622ff5f1c2b797c48eb6df50ae276c51e78b34975823439f13' 
  AND token = 'I3LwLeuUp8JZQx0WD4D8brcFctaacUv2BRI07jMuX8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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