SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61411de0a631e7248a3ef7559546589607db3ce33741d027dbbb78051adb6619' 
  AND token = 'jPJyu6hiIYbOcMhgY/dBWDZkearrZBTSbirxE0uBeY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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