SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '879f2d388c6ca9098f9a0eb11bebfab922d832846631e767f757822bead128a7' 
  AND token = '8JOd+eo4fDf8dSY6EQRzjVWQmzEbWmBrxGnILST7yL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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