SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6284a7e8dd4ba2387076c851957f7b12056efb77eff3181bc829edf42e97e49f' 
  AND token = 'H1k9HAJwhlhyURq+amlMt5DA1w/sDvOthYyyIvNgxQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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