SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6cfb8474e20f064e17073ffdb63f50e91714b93fba6f2e166c45b5371e1ae13' 
  AND token = 'gbffzcMy0SpzSIGk2j0GrvJSIiM0RGxjVuVlLvfynsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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