SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '964bf2673692ac64bb9539c210a29fb4aa877456287511ae3d9d258f31f0a5c8' 
  AND token = '+ErFkNXkSfHhykyELnSCyefeyD9jkgGBpQFfwb3Jwm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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