SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e38abe45601b489f7c73a216924400079047fb63c5ef5cddc8c318af30adb32' 
  AND token = 'kOXLh/HZwMnhuz5ySAyYFx2CGgyzwApjEro5LSzNdNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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