SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '838244ce7b932c672fcfad900c689f4175583316c98b76628dbd18a34df45bf5' 
  AND token = 'koLIKNV5YBKcDPJpAZoAwxBga1LjmaXs0V5LUzPk7KY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00075

JSON explain

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