SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b47057278a4c9b834edcc90c629ddce516c6db38b0739aeb26c3d8f14a9405ec' 
  AND token = 'cK06N7wWnri981B9kZvALPpxwSgwOE/b2bZMqKoKh+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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