SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b4f91549950f1744dfaecc90b462a765cfafc5f6abc2246c6ed6ed56f5c27e4' 
  AND token = '4BWW8bZeUCyYmjJ2XHVMTTBq3tMWEIdFxp8/Vk41syc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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