SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a938b4fc2c2ed4c76ffde938e928bd6405c78e89a2794cb6f02d47fa6953534' 
  AND token = 'KTttUZdOZcYg7ewvUnxrr/nwgbVLGMHpzleKZNWtG3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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