SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e341336809b03d5edcdb4be49486fe69c04e1e0746163e599dedb09d3db75aca' 
  AND token = '3xq8xuxtZAOLQSgA6qxfcivHNFZDOv1lAaDEzVJWh0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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