SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '575f633e4788ab3223d6f3cbdd39391176f7b12b07580448cca34e9b23643b6f' 
  AND token = '4rofsRw3ZM9MbQvBhzYNVnpwGe4Mag2+Zr6qL6ePrTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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