SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42160b6306cbd5c1d187665707669febc1c7a3b21a0b4daedfdbd8deac47b352' 
  AND token = 'WY0w74ZMHJLlWnpWF/2Sb1GiXI8+ERIKxvaaOlQbLUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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