SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a7bff03830a18a7e238dc88336bc05948819be3953cc950014d51977c3bf2bd' 
  AND token = 'HKvaNcjbpJZBivFu8AQcupOpVxAgoaSgD3PK4zKyUfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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