SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a43533986918d7672ac5363fa57c5f96f56c89fcc23114bf8440c3c0818053f7' 
  AND token = 'llruSTLAHlzq+JevvMnuMZgI64t/mXddUVi8jbJF0w4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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