SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd625c2523f06eadce7bffe1a8e17b4137b4f478896f6dbc5a03ef637fd5bc614' 
  AND token = 'tgyx6JPRZurVv1QjfDjTJQ+04YUFU9CniWBFiWrs/N8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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