SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2835afe256642fb308cec0cd4517dbc697048caf1ab50e2461fe37ddfa541257' 
  AND token = 'EGZK1nvclgKim9KHkSGJYBF89S6XHk1/cK6H1nkUwwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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