SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82dccdd6b03f35520d1d25ab15fa2bf935fffd113d0e545a1158143b5d96c0ce' 
  AND token = 'g1Vshbp1c6vdPBzRzlnb9DJ6DQNEJENBs0ikR+lN1JY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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