SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2fc8f395c541dc94213f2fcde76e58a59430bb9333a59ff17bdb65b22274f7ff' 
  AND token = 'I2NxLptN6an8+VumFJBQdnPl9qY/0e33tShWrKBsmrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}