SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c74ba74e630210eae16f778ad3469fec1865faf9818ff5f81396b4ddc0fa3cd7' 
  AND token = 'Jq3JI1cjvcGez2qZFWtlaLfrmTdEspfmXn4VPX4OTww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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