SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be50ac1a40d99ca8648573b4519a74af7e4a9a1a5b51a82db7154a6f023f4929' 
  AND token = 'UHJtEvv4m3SlmpDfJg5INapjuYqeX6PoCdYr2T6QEiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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