SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58769816e781f2f911a7696af6c5566bf3bacd7e18f49561a65c4b67afdf1e93' 
  AND token = 'fPQQ4eiuhKMY0vHRed9mhcsu//A48z/0TDhV1VZVW7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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