SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a94da04da7505bf2141c6603dd535ed2630cbb075ab0fb5f09dadd9c0fa636f4' 
  AND token = 'mRpZuN1OdOOauMTw+wN8vaiLH1FmouzGMCAYfrk/yTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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