SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81ce1a409b1925cf74f22a4e0de56ecebbc70b494d8a9f92a9cc2cb2decd824c' 
  AND token = '26Tv1MHIDSFYiiQDvGZ8VJOXg95Rj09Y+WP5VTRQp78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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