SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ba8ac1357188f1fdc027c0cd1d6e264b7844d1d887c1ccdc97a45dddbb6bd91' 
  AND token = 'lw3BtwPKYcsJzpPg+CJOOY2hkzMySR9+4REw4Z2zceA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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