SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccb38e24d1b64467ee80c30a5c894c4cbd072746cd9e3c805b2b2fb6f9cfb9a9' 
  AND token = 'sJAwta9Mrh5UwGIyeZrncV47MUhHSjGsCDfoZ3q7yQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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