SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fde8facd20263fa1aadb2c118ead58e9802a23ba9f65509a3af604b91afce75' 
  AND token = '3g4DjvYw17dTSBZiVohBKbREwYOb/T5KeIyup1+bY+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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