SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3595f77b8acaa25afc0729f814d83b40384d8777a643e4df418dd5bbf3971743' 
  AND token = '1lp3kpU0jZ/GzJC7ltvCAxiAPFaCo7b7h+19kNkF/i4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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