SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8aea087de7f70705881196a908616f15f5b936ec5fb2a620ba50a67057e823b7' 
  AND token = '4yACsqrwMZFIcAKqavd40/fs/iIsDjWkVoIi9Xrkw9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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