SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8ececfb4147b91e7cb4407ffd5826202a8a3a80f9f0ca37e492ff778806b3cb' 
  AND token = 'TpK8+KfXDZEQ+q5MfTpxu94EppncDVoZcqDvwKHeJj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}