SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3bbb7d44f9eaed92d39b1ec756b46159c5355cebe4a2bc8e2208e514e1af09d8' 
  AND token = 'ZU11f4U7+ghTFtQFI5Eif+LrzLsh9/eYoKCHe818NsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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