SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c704d2d708cf1ec2362aac33c570111d7794865fe3afe21c8985c06a422b4d6' 
  AND token = 'RGSD9PRyPTUTCIriXeqp0kVF/wuWSPZmuvzi7L5fEzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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