SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6584a095ef56a6ef6276cfcfcc048b37e372496fe4eb451e4090cbab75f3c931' 
  AND token = '3YmVLuTdKnADniO/Kwv2nMAOe+F7yMnSH6cyRoiyddk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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