SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f099e6f8e431fedd566be95c22231c549e87fe02f1a9adfdfeb0c3dbc13492c' 
  AND token = '5CkbQB0on8SgM1qo3303+yISblFr1UOGg07R+qDsYw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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