SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c439fc38ce6604e244afafdc79f49abc8a6e51726d69a0e94bbd3355ebe8f8c' 
  AND token = 'eH5gWUtjolHOJ9RFoY3ZBlZG8B7r1qW3BT8iizuzGwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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