SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb4aacaebf976804437bc6d0122a140c3385168431b5b8ffc7635c76be08340a' 
  AND token = 'gAAToY+edQYByRLPV8q6Xxfj3TCYOOewmiM/wSPK/+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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