SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54210d0dd9df231c1cc32d271c45cdb7e6c5f1ecaa15de46aa1ce84cf8847040' 
  AND token = '7/B9mh6PmGwqitR+kjsEW5BnVy1LJEkV/oD+DHk1euk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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