SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b62b79bd6a061d8989181d067aa02d85e3cf5a160d3fd608b4c95d094f80e462' 
  AND token = 'hlVXB3isrnFzvA8fI47rzDGzXj8HSJqQGA7RzmZunS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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