SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd449926f24c08b6ef2938869d21e74c853f40955f0b47df9a6514e2ada4728aa' 
  AND token = 'Wvedl2ltPzuWn+xUU25AjRgB+cnC12wbJbiktgxeOpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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