SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cd6eb5db2f4d18929afa118d195d317e4b0c7bc268788bc6230478025e7728b' 
  AND token = '+SHqnTb9N64LAJHGWofmbuBCKFVz2hhIQ3HLueVj9F4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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