SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03c0c108621f5f72e1af970db3579646eac15f7e3c0bed8bd082435525e6eb5c' 
  AND token = 'vnvpMytkYbAggl0Bb8r1PO05d3WJbrVXeXEUrg1r47Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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