SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '549277d4a864e5a1bac14441d7292e839bcf233951f80f04c083703e56f3d9d4' 
  AND token = 'dwaVSt0ow0xIE9Es/LIfQ76qd4zxXebot6Snd0DJjC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}