SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e2f92788798c5310c104f439b8851154aafa5cc67edaa56f48e535a5e73cec9' 
  AND token = '5sRYnboJKai+DY3G7Gs9K7+54YxwtitTyZGcqIJtn80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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