SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0eed843a8eb3380f381e4cfea86667b3baf8e7f05a79d3588c887e6961d21d43' 
  AND token = 'FO4zouBnXB5nW1KXfDozTHTN6y6Rque4UulmIPkCxyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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