SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78fb681e8ef90924f926e10cf461bbf1e28ea5885f496553f4a4bc0c33057335' 
  AND token = 'YGtMDzBUaP7N3Cm0K54nebrYtjZnJBtXvhL/zxapsPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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