SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b10c8c48d20eacc21cd934b5b6a64f1b23d59feac9040f12bad1f83f42fcbadd' 
  AND token = 'qt5cxuGU5nj/PvzzmJvN5+0QFekY2RbStnUbWi0ZVXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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