SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37961386bfb465a8da4b487234d2b314770417737a41c221e701fdb8a4e4fa1f' 
  AND token = 'KcU6oXQdHUg8FuIeB+UgYGmpcqAyzRvbtVqh71vReAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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