SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97c123d47057566c3011350afd715e895209800d5256031d157ce39774dccdf8' 
  AND token = 'vYrT7lG1sOLAQ6Ut0IOi8B5OJ53L9F314/PhngIYsOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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