SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f791602012e061cc0bbb60d88143a7827b9e5c288399557782e087be0bc2c891' 
  AND token = 'gnPi6GqX1ZrClgLZuiiDIavGuB1ERfqpHkSn4fI0Z9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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