SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f10f66fca604012411148c598a7cc59f4a3182ff10705b0596ca5251630ca7a' 
  AND token = 'qtzcdGJ8x7a1UsxUSEy+pJidsdLwjAkoQvk0e9Bp3Mk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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