SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44f341be124cf7195e88d0fe67c9fca0b88cdab759f26db859aebcda3214d5e4' 
  AND token = 'h63QCRXwju+rQa+YL0nKI/u0tcyDzfUGZMCpNKlAwUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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