SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8c53b0e452fb53d9a93a8d426626775dc742af2bd7e06bfd2f2c90e224957f6' 
  AND token = 'xYTNDw56u4Tp1BD7IoMzsUSi8KdkfRKkz3FcoTM2wnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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