SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bfd6bba5440cc8c0d642b33da09cdffef13ca998470e13fcc9259f0d684ea28' 
  AND token = 'HSfmKrideqV70so3zXfrxP8PjAKiCpangZ0oudwPSPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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