SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c0e23c61bc063865a19e5f1758f8baddfda30feb415ca27562bb50bc79279d1' 
  AND token = 'L3vncj9Mv9UbXklpxe0yETKRriJVIPmd6ty6WmWP5co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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