SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36aff8cbe9b69eb6bd00f08db433ee0b0f21d4370cee0e65b239f46e46e042c1' 
  AND token = 'YUT7YWksSyhJ0dRvbX3XOp0IvQMqiTynFLqAhodxspI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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