SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b002dd8b5f15724723d131709ee383084215da748888b6f55c1201bbdba1539' 
  AND token = 'lBsaHXRi8t82zMbQT/jOuVqxdEoIOhS5TzysrlOZwHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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