SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b900abc72f318db84d5cc1c188f26d95649fd521db4618d660305c6ee97197bf' 
  AND token = 'atci/HJI7QX1JpC6ue+nBcRPr/IJ7Z/9Gq93KHZY+gQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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