SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8263ee7fc36b28965d77fe23defe0872d15d45f0b27cfee8f2ee48d51d77f657' 
  AND token = 'kLGWZWfMW/rqxxElfyQAbxbsA2zbxPNBqmaa9j8KHQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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