SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd42d319a4b8afc7b480ae8ad81357e7d35121d376dd8f55d800853aa79d83454' 
  AND token = 'SjwTfHBuew6JDKe0FFVddpW0B7R6qDgrFJ9v9wnib1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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