SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b757f6821da5873e979eca9e4fafe2e6d79f7ef2652aff89f912ad0f8503b1e' 
  AND token = '98g0xWVizl4Ak3Nr4pQh2nzI32D36tnSx7QLRr5Hk6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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