SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caef0981383eb9a3951eaccc6b95bbc7a4b477848357100abcf5fe21d0cf4b14' 
  AND token = '9S/1S87fem4BV8v9S6ZFOLjkCE+HgzGhHUzE8aRjBIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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