SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '890071374fe65f507157e7dc10ebd22a7a579595bfb6f95208a0e513bfd1481a' 
  AND token = 'CqupbsSLrgQCYYTGUCgW8AqaU0WEg88mNtD0RyGohbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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