SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31664f82c5f552055b41ccd3c42f144f93b10dd28875e1f99a1f97ee0eb67c48' 
  AND token = '7PanDHhkNBuQ1fiOq8PkrtuJp9TJ/3GZ0mywnnz/mX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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