SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c52959694e357cab05788960a69783efd02082ccb15701087e80162a54129870' 
  AND token = 'OSQzujuCQt8i09RfT3PlljbAgbVQf9Kp8th5CpUVyQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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