SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f72f0c6e33e87883eef78fb6f4908a58dbd3be9baf8ed8a458945aa4104b45f' 
  AND token = '6o7yLp0ycGlJcqHIWKckjEADjKTiX52oqdBI0uYIHJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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