SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '010bfe5c7877036683f0fef87488559df1f90fc27a373f9da6304417021c8895' 
  AND token = 'ErtUYFjl86uvaS8j3BqKTZY9FfMhpSemOG2lXCBvRQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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