SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd540b7af46b7f9db524d22c111bb8fb6959142b8844455367c2cf5b37d2672ef' 
  AND token = '2fMEHeGIootgjrm0LYrjzbMhuSufJQzJYycy2MD7GPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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