SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bd06c5698f92f720be79bbe2d135593aa13bc06c621e5c9f2e3aa06d5f0fc61' 
  AND token = '5GSeL/j1celybPRnFjfFpcYajsvQLLDYhMUKR9UGNL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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