SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abe9f189da1b5fa8fc1c8ec987c1fe502197eed4e0dd1fcd8b75da0833333b9f' 
  AND token = 'Ilz4YDYfMnP6fKtbuEOyP81VSaZhi40Jf8vDHEaZVt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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