SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '640fe0cb57b526149c7cc8dc8c3c4e6ea794d642a792a094f92e3a389415897b' 
  AND token = 'AWG/RmKU0IXdw0a1+UzZc77iYYB+vNrH/7y16MuWvT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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