SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f942068a6e1fcc69fcb3e1222edf174e066cd23d6772b1e93748ca5dfb89417' 
  AND token = 'w+F6qQC+i+MWJqZyC9BgA0NqX3xaAjVy7f5AWl/LbJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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