SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b13f95e416879d987220d992fcae237bd0a2926930181da816def37b19935a9' 
  AND token = 'CQeWgsyla7YB6CMIaIURoi+3SfgcJ5tWqqXMVui42LE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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