SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3089942cb20937a2dedee1d700480c05c99d5dd816ed82b4c60c5131b739f280' 
  AND token = 'f0LGu5kbDutnkhRjCWRiXrcC0590yoMDL2UIBG9pjas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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