SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcd97716a4120ab8ec8813868ad1b844ff98fe314119483d6b86df226f758989' 
  AND token = 'LK7lnFZY8L9DVAMnrSgbT32MyVZAWDCZ9/UajNTBQgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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