SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f70cf756a457242657e7c996a006f25d5b8a6cc88f2bc4775bb5179cc6868641' 
  AND token = 'M5ICttJPs1RNn8OGlWLLYVZqvZDewoynMjcrQMyyoFc=' 
  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"
    }
  }
}