SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca2974e8182f22806241145e7c566d52e1d2d34e4c0582621651541231821783' 
  AND token = 'kZJ36xylWUD0hblEM7WsK+ge3oSeB3mAgwK+XSNkPvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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