SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e19e0d03cc59a406ca4cfaa88654a14c138f62af15f42203ae8363a51c6b46d8' 
  AND token = 'cjLi5yer6ozokvy2TBRzJhW9iUX+jyFoXfFavRtZ200=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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