SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56f32600c155260b2beea0b279b432609eb3286e131a025379f989d55eaf7819' 
  AND token = 'ZScHmYzN8KWD5H5Y6qgTDCaAtPKrn3NMkH4bPjicDWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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