SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9503b3325decc45ac383a51c60c5d17c4b08ae50f5b388c4b37e448f4ae22a43' 
  AND token = 'dT6QEMn6AkH5UMu96soxWyYX5nlbfiZMFxzNoHa4N4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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