SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd91a8867303eeed6600d5f92c43147688e659885ab3bcb85207ad89d5fd9a0ba' 
  AND token = 'yvPyt2ZNTJ3M61kiTGFS/UN00kz2nBpgjWTMDbwpDYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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