SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23379016379a5349ea0ad6e1d69150bfe723fc31c9abd18e4fd3faee3efa5e65' 
  AND token = '9PKd58vKViVilW+7c1gnuTCLLaiy1eUe+SMm989mAjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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