SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '955ae4adcd74463ef818f061752604f3ff9252ae7398655e82f9261780eca54c' 
  AND token = 'WOMhyLSlBBuyISHfxzYLL0hHEaD3gbTbzp16TPDW3ZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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