SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d0ff60a6388ef04f38ec141ebbabb2361d31c04c9aebf840e551909a32e10f7' 
  AND token = 'Ji8hHu+BdVRcxUjGFV0mElw7v51CtT7App4qN9Is8Yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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