SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45647585b9fcbb459dd254e5693fb62c79134d9635dc5dc972c45ff1900c6826' 
  AND token = 'h5ZCJnr5ovPv9+5I2ssl6kwt+cHy5YQAxdQsnaaQZW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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