SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '193876838c8b4e81313901e2f2923531f4cea7c37dabd04c40270e8dd5aa60ba' 
  AND token = 'u8S+/G5F1CzxqsXqAZWUegGSoYl7PYom7RQ2JmrZLh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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