SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dc60872e3016f08ce103f74b062907911e2e217b8b7bc2341287f98e08b7aff' 
  AND token = 'eAuekzd4vWQampk776fS9vkk3YmjysM1wJcrUASQXV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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