SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30d38402bafe21d735663125dfa22b51d99750bf76123f1dbd9e220368b13472' 
  AND token = 'HPtGs+Rxh2QlAl7p7hQFvgpCfBWGBBMmLnRNEUaB/zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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