SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2826bf35e1a110e7daebdbec29a5d7b5b36ee42da45ab3934fefc1c827bfcb75' 
  AND token = '5meO/X471ooSAgNqw3rhVVvJNforaOuWEW5xrhGCufA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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