SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0f5a11af59b4c24fad42e572b6843317467a2cac9ce0991b45dafa7b265900b' 
  AND token = 'CbNcJUbchcVTQd+bZqmiHiBED+qihr2yZDLcL19dpuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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