SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4c6befdf58301430ed6668e1a9a8a7facd5b812842cc5df91ae86c6676a0aad' 
  AND token = 'wYWhDfiZ0kMnAx2vkLXI+Bo+gQpwALKrgEPyTw1NSXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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