SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3217593880c6f418cedcb99fc71eaed3b6526299f87365d120340619719b1eaf' 
  AND token = 'tsYGHSq/QOXL2+8BqXvjDAbXWPPmGVkNqmy189yYY2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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