SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d3618388c4fe590ee62f63740928bcf494482976ab662161f8ae4b15c4bf3ec' 
  AND token = 'MjNkzl80Qwji9IK5DCB8IFWlRBw0FT90udF02xDqKNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}