SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89695c520a80e18663fbd7c747580912f83fa48701b007a98ae425d6404ceaf4' 
  AND token = 'LV6IBlB4SDNs5RqCjkoZNYu6EZili5yCCnUQCs8pSjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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