SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eab484005f8ccb1bb8ab8773fb6238cfe4c56d5292902ac5344c1a27882e3968' 
  AND token = 'YzReyvSlQIojT/UpKwOr5PwDBswWpRz04lD9kKYhGMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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