SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb2037d363d6016a3843fd894ae53571ab25f5150acd45063505a4961ee2bc94' 
  AND token = 'Fj5BD0bDe+SsKVXjEeLjC/6EPQbdYG9zvTsQmcJAxxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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