SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93b6b9db5c8958442574aeb6ba06200dd9a63c7900c7aa9af61aedacd7815b53' 
  AND token = 'b12rLhbN4YZMThDHhIaxSTmEbrs9hs7HsiNOK+KSpJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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