SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a68e76e3f94f402f16672e3ca186ba233d8ee9128a92ca57ce1b539c4e77b24' 
  AND token = 'NAZLsOdoNtt+S3Z3g7tfr+yo+fZCDZzlcnb2xuTId2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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