SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73b7ba3b01d415e7e654ee8bda97247fc7e3c765bf3dd909497e829bd9a0a417' 
  AND token = 'kO37hLMaYyhnE3eeOvlumMzHLkJgNm6m90iZgOrkeSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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