SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8f8c7f089472ee8c68bec98968284428fabb246e0a2bc860cdebed16b0dba6d' 
  AND token = 'c4eUGNg45BspPBhfJX9dEC2dLsRhSp3oRyzRMgZhMRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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