SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c899cb2b571394f8bb81f5b87a71c7dd2a91557b8dfd99ded51b1e007261083' 
  AND token = 'IxQprbYWluD9N0iZjcYq4XGSiUSBbRcspXFQp8sl5+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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