SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5768c2b03483a235105b3ec706c0c9dfbfba633ab547926689c3d0e1b921eb30' 
  AND token = '2AxQZWTA8/zC0rrvb2d3AlygYLhycEsZkEdZmxbebBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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