SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c03bacfb75e692a36d9f3071aee7842e7b2305ed1fd0247613e37aa147d1cc90' 
  AND token = 'VSiXkSUvzXZB6jR3jI6ytJ93FTUjAnUWXVbLtv2QInk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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