SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1798f75be80a4048d5b0104f03f58b2381ee8cdd0fda96f4648e6298128b4c28' 
  AND token = 'd3V9q784iwHNQ4cw+rdqr/zKg20HrHK5rc/2t8uhx44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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