SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac53eeb373b3f521d30bf839ed6194fd18b5bb02d9d69257086375b3ddeaaace' 
  AND token = 'uwUbzvlvVozswdldDjwUGaRWx5oQZxGgMLlu/HSHO/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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