SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '362da6316c09594da9191ae8d460d350bdc78330f55d29e88985923dd01f1464' 
  AND token = '8tUEXszvWZzar5OqH+b0yo4bW+ecwsmUnQHkEJx6Puo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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