SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ef90f3133b80eb1265c3def45aea43469961479f3b0af0411226bee0141872f' 
  AND token = 'EYjvVpevgc39f2lrvL8rlbffovZTswEDwarpEA0jQ68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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