SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbfa4b68950bf114bf273dfda5020b0dd7e7cf2e3c043a98032f5c17d867bb81' 
  AND token = 'tFrlsOF2h+kKVRI+8jXXz0cjEBcQqt+reoAp7ZegNHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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