SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55754ba3fb2e9855446ca734cfc395787c800a157c35b9db7aa05982f7a59803' 
  AND token = 'dDVJ0mPJ7v+zvcA6PHCfS87eEmIywQ6lud9ArY2M/e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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