SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '854e588701230996ff1762f987f094c585d04a65af5885340cf7f5949e6abc7c' 
  AND token = 'CXMt9c5ZZjRapqZhL/qVhCA8RpSoMEWA+UPrdEzWEkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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